Tilting salt bath furnace



June 14 1949.

\ TILTING SALT BATH FURNACE Filed 001?. 26, 1945 5.409 zz Z01 G. H. sGRENE 2,473,095

4 Sheets- Sheet 1 June 14, 1949. e. H. s. GRENE 2,473,095

TILTING SALT BATH FURNACE Filed Oct. 26, 1945 4 Sheets-Sheet 2 flag/4.207 G'eazzze 29 5 G'r June 14, 1949. s, GRENE 2,473,095

TILTING SALT BATH FURNACE Filed Oct. 26, 1945 4 Shets-Sheet 3 FIG 4Georgeiz'emySianlcyGrene Patented June 14, 1949 ..,2,473, 085"ZTIIiTING'SALT BATH'FURNACE Greorgeiilienry. Stanley Grene;Watford,t'En'gland,

rassjgnm mf one-half to.-Wild,-Barfielcl;

aLimited, Watford, Hertfordshire,

Furnaces ..,Eng-land i Application-"October 26, 1

Electric in Great Britain November 1,1944

.--6, Claims. 1

It. is ordinary-2 practice tofaztilt: melting-furnaces where thereisax-moltenychargewhichi can'so'v be poured. -.jSa'lt bathfurnacesr.are,:however,cused forthe treatment-bf solid workslpiecesvandit does not appear to have hitherto to arrangeihfor remowal :of the workby usual ..metho,ds.. andito. .tilt .the. furnaceawhen the. salt is tobe removed for cleaning,.outltherbath or to provide readily forsubstitution of another salt for a diiferent process.

The rpresent inventiomprovides a tiltableasalt bath: furnace, enablingthis eprocedurerto ebe --readily carried out, and so-otoefiacilitatewhat is .otherwise. a laborious job of bailing outithe molten -salt--tenable the accumulation; of sludges-at the;

.bottom tobe removed.

In. the: preferred forms thervtiltableubath is readily removable; incases where thaamount of -work-to becarried out justifiesit, separate:baths can thusibe used for the several saltsiandtheo rbaths can bechanged so that contaminatiomdue to residual salt in the brickwork doesnot take place. The'--b'ath--with its electrodes can be immediatelylifted from therbearings and another -droppedirr place.

- The above and other;:-par-ts ;vof theninvention are embodied inatypiealsform illustnated'qby the accompanying drawings in which Fig. 1is a front elevation,

Fig. 2 is a side elevation,

Fig. 3 is a plan,

Fig. 4 is a fragmentary sectional elevation, showing the bath structureand associated parts in working position, and

Fig. 5 is a similar view showing the workpiece removed, and the parts inposition for pouring and. collecting the salt.

The furnace comprises a body portion I which houses the conventionalelectrical gear, enclosing a contactor and isolator indicated at 2,step-down transformer at 3, controllable bi-metallic strip energyregulator at 4, amrneter 5 and indicator lamps 6, tapping switch 1 forthe transformer with hand wheel 1a and knife switch elements 8. The mainisolator switch handle 9 is at the back and a push-button type emergencystop switch ID in front. The body portion I has a pair of forwardlyprojecting side wings or brackets II, with elements ll of the rotarysupports for the bath arranged to receive the complementary elements ortrunnions I3 on the bath M. A removable mould I5 to receive the salt isconnected with the bath by a, channel [4, so that when the bath' istilted the salt can be carried on the front of the bath and may have aserrated or other apoccurred to anyone .propriatevsurface:"l5a on whichthe salt' will lie wz-as {it solidifies, so facilitatingbreakingitupwfor -;use again. The electricalleadsbetween the body portion 2 andthe bath arereadily detachable for removal -of thebath and as showninclude knife .blades l6 adaptedwto engage thefixed elements #8 whichareconnectedto the electrodes l'lizSO :thatthe electrical connection wis:automatically rbroken whenxthegbathistilted. or removed. A -10.-,

cover .18 carried by the-back. of the: bath encloses the;electrical;lconnectionsawhen :the bath is fill itsnormal'uprightposition.

The use of the bathandythe deliveryof-the salt; from-,.-the.bath tothe-removablemold "i5 is .is shown-in its normal --working.-positionwith a wworkpiece 28 best ashownin; Figs.- 4; and. 5. "In Fig-.-4 the bath suspended from-the branch 23 .of

-.;the'tool post 22 fortreatment-in the-.molten salt -ralso=beemployedas; a tiltingr-lever. When the On .the.-other hand Fig. 5 shows the bathtilted as by tilting. the tool post 22-=-which may -bath-is tilted themolten-fsa'lt is conveyed by-the wchannel passage l4 to thermold @andsolidified after which it may be readily removedfor recoveryof the-salt.-It. is to-be. noted that the electric circuit to the electrodes isbroken at ,the beginning hot the tilting movement. by the swinging ofthe switch blades l6 from the switch elements 8.

The bath is covered by a hood I9 with lugs 20 which centre it on thebath. The hood is provided with an observation window 2| that ispreferably covered by a wire mesh or perforated metal sheet or thewindow may be formed by juxtaposed perforations in the sheeting formingthe hood, In addition, the hood is provided with a relatively smallcentral aperture 2| for the admission of the work piece 28'. The opening2! is relatively small and centrally located and the window 2| iscovered by a mesh or the like to protect the operator from splashes.

The work is placed or suspended in the bath and removed after treatmentin any normal or convenient way. As shown, a tool post 22 with a worksuspension branch 23 is remova-bly supported in a socket 24. The toolpost or a separate lever can be inserted in the socket 25 on the side ofthe bath to tilt the bath when required. A portable pyrometer 2 B isshown, carried when not in use in a further socket 21 in one of thewings.

In many cases it is convenient to provide a series of adjacent saltbaths for successive stages of a process; for example one or morepreheating baths, a hardening bath, a quenching bath, and possibly afurther bath for secondary hardening.

The wings or brackets of the improved furnaces can readily be arrangedto be bolted or otherwise attached against those of adjacent furnaces,so as to constitute a fixed battery of successive baths along which thework under treatment can be progressed. Bolt holes 28 are shown for thispurpose.

I claim:

1. An electrode salt bath furnace to treat solid work pieces including abath having an open top, means for carrying solid work pieces in thebath by suspension from above the open top of the bath, means fortilting the bath, electrodes for heating the bath mounted in the bath,electrode contact making and breaking means for making contact when thebath is in normal position and breaking contact when the bath is tilted,and means separably attached to the bath for receiving the whole of thesalt from the bath when the bath is tilted.

2. An electrode salt bath furnace to treat solid work pieces including abath having an open top, means for carrying solid work pieces in thebath bysuspension from above the open top of the bath, means for tiltingthe bath, means separably attached to the bath for receiving the wholeof the salt when the bath is tilted, electrodes for heating the bathmounted in the bath, means for removably supporting the bath with itselectrodes on the furnace, and electrode contact making and breakingmeans for making contact when the bath is in normal position andbreaking contact when the bath is tilted or removed.

3. An electrode salt bath furnace to treat solid work pieces, means forcarrying the bath tiltably and removably, means for introducing andremoving work pieces into and from the bath, electrodes for heating thebath, means for tilting the bath to deliver the salt from its effectiveposition in the bath, removable means carried by the bath for receivingthe salt delivered from the tilted bath, and electrode contact makingand breaking means for making contact when the bath is in normalposition and automatically breaking contact when the bath is tilted orremoved.

4. A construction as defined in claim 3 wherein the means for receivingthe salt upon the tilting of the bath is formed with a serrated surfacefor forming a complementary surface to the salt solidifyingthereagainst.

5. A salt bath furnace for treating solid work pieces and having spacedelectrodes, means for supplying said electrodes with electric current,means for tilting the bath with the electrodes, a removable mouldcarried by the bath, and passage means connecting the mold with the bathfor passing to the mold the whole of the salt from the bath as the bathis tilted.

6. A salt bath furnace for treating solid work pieces and having spacedelectrodes, means for supplying said electrodes with electric current,removable cover means attached to and overlying the bath, an observationwindow in said cover, a work admitting opening in said cover, means fortilting the bath, a removable mould carried by the bath and receivingthe whole of the salt from the bath as the bath is tilted, and contactelements located under the cover means and controlling the currentthrough the electrodes.

GEORGE HENRY STANLEY GRENE.

REFERENCES CITED The following referen'ces are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date Re. 16,054 Moore Apr. 28, 1925696,004 Burton Mar. 25, 1902 749,403 Rousseau Jan. 12, 1904 863,469Thill et al Aug. 13, 1907 1,032,217 Johnson July 9, 1912 1,070,568 WileAug. 9, 1913 1,370,989 Nye Mar. 8, 1921 1,601,703 Patterson Sept. 28,1926 2,367,897 Smith 1. Jan. 23, 1945 2,379,651 Pritchard July 3, 1945FOREIGN PATENTS Number Country Date 27,836 Great Britain Dec. 11, 191224,850 Great Britain June 25, 1914 291,450 Great Britain May 2, 1929

